We plan to study: (1) the action of phosphorylase kinase on synthetic peptide substrates to establish its specificity requirements and mechanism of action (2) the role of the subunits of phosphorylase kinase in catalysis and regulation (3) the specificity requirements of phosphorylase phosphatase (4) the role of the amino terminal segment of glycogen phosphorylase by chemical, enzymic, and immunological methods (5) the action of pyridoxal and analogs of Vitamin B6 on the structure and function of glycogen phosphorylase. BIBLIOGRAPHIC REFERENCES: Parrish, R. and Graves, D.J., "Irreversible Inhibition of Phosphorylase Phosphatase by Fluorophosphate," Biochem. and Biophys. Res. Commun. 70, 1290-1296 (1976). Carlson, G.M. and Graves, D.J., "The Site of Action and Biphasic Effect of Neutral Salts in the Phosphorylase Kinase Reaction," Biochemistry, in press, 1976.